Well, considering the fact that I've now read several posts where people have gulped down those unidentified potions they were carrying, I'm introducing a (sort of) safe way to test them.
If a character specifically states that they intend to taste a potion rather than drink it, they will only take part of the effect. "Tasting" has several distinct stages:
- Take a drop of the liquid on you finger and see what it tastes like. No effects, serves only to provide more information. For example, a Potion of Polymorph tastes like "An extraordinary combination of flavors, each lasting for only a moment". Players who choose to skip this step, will receive information about the flavor in the chosen stage.
- Take a few drops of the liquid and hold it in your mouth. Extraordinarily mild effects. Does not work for most potions (10% or less). For example: The players have found a Potion of Growth. However they know it only as "a black potion, with strands of white swirling through it like fog". One of the players chooses to taste with the result that "Kedru appears to have grown infinitesimally larger, but the effects are so faint that it could easily be your imaginations. Do you wish to move on to the next stage?"
- Take a small sip of the potion, but do not swallow it. Effects are still very mild, works for about 25% of potions. Assuming that Kedru's player wishes to continue: "You have most certainly grown larger this time - about an inch"